Conventional slide projectors, especially those intended for home consumption, are usually configured to access slides of an associated tray on a predefined basis in accordance with the sequential physical ordering of the slides in the tray. Slides must therefore be prearranged in the tray to match the desired slide projection sequence, in order to avoid having to cycle forwards or backwards through unwanted slides during the presentation. Should the desired projection sequence change from presentation to presentation, in order to have a smooth show it is necessary each time to rearrange the slides in the tray. If one or more slides are to be shown multiple times in a single presentation, duplicates must be placed at corresponding multiple locations in the tray. This not only incurs unnecessary duplication expense, but reduces the number of slots available for other slides in the same tray.
It is desirable to be able to randomly access the slides in a tray so that their presentation sequence may be varied, independent of physical positioning in the tray. Projectors that include built-in mechanisms for enabling random access to slides in a tray are known. Such projectors are, however, directed at the professional audio-visual market, rather than the amateur or home consumer, so tend to be expensive and complex.
An example of a conventional random access slide projector is the Kodak Ektagraphic.TM. RA960. It has a large controlling dial attached to a dedicated projector with provision for spinning a rotary tray by means of indexing pins located on the bottom of the tray. Sequence numbers for a show must be memorized or written down. Slides are manually accessed by turning the dial to a position corresponding to the slide's position in the tray.
Add-on devices also exist for converting existing projectors from sequential to random access systems. Such devices, however, require modification of existing trays and interface awkwardly with existing projector/tray connections. An example of such an add-on device is the Instant Slide Selector manufactured by Fairchild. The ISS device works with conventional projectors, such as the Kodak Carousel.TM. and Ektagraphic.TM. projectors, and consists of a selector unit that attaches to the side of the projector; a code ring that needs to be installed on top of the slide tray; and a remote control unit for entering a desired slide number.
There is a need for an inexpensive, convenient means for providing access on a user selectable random basis to the sequentially physically preordered slides in a tray, conventional projectors for home as well as professional use.